


Worth The Wait

by MeGaLoTrash



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Anal Fingering, Anal Sex, Dirty Talk, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Guilt, M/M, Mutual Pining, Overstimulation, Praise Kink, Public Sex, Rough Oral Sex, Sensitive bones, Sexual Tension, Spine/rib Play, Swapcest - Freeform, Switching, Underswap Papyrus, Underswap Sans
Language: English
Status: Completed
Published: 2018-03-09
Updated: 2018-03-09
Packaged: 2019-03-29 02:41:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 8,507
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13917663
Author URL: https://archiveofourown.org/users/MeGaLoTrash/pseuds/MeGaLoTrash
Summary: They knew they weren’t meant to feel this way about each other… but knowing that didn’t make the feelings go away.The Underswap brothers plan a 'movie night' because they're being driven crazy by trying to deny the heat between them.Swapcest Story ForBeoteono





	Worth The Wait

It didn’t matter how many times Papyrus turned the handle on their front door to make sure it was locked, no amount of double checking was going to make him feel prepared for tonight.

He moved away from the door to go and lock the door at the back of their house, barely able to look his brother in the eye when he passed by. Sans was busying himself with tidying the lounge for their ‘movie night’, even though he had already spent the best part of the afternoon stress cleaning the entire house. Not that Papyrus could blame him. If tonight was really going to be the night where they crossed that line that brothers shouldn’t even think about crossing, then Sans had every right to be nervous. Papyrus just had to hope that his brother didn’t notice the way his own hands were trembling as he fumbled for the right keys. He was meant to be the big brother, but he was just as terrified. Papyrus thought about popping outside for a quick smoke break, but he’d been abstaining from cigarettes all day. Sans hated the smell, so he guessed that his bro wouldn’t be fond of the _taste_ either. 

Papyrus couldn’t remember when exactly his infatuation with Sans had started, but he’d been head over heels in love with him for years. His baby bro was just so kind, so sweet and innocent, and didn't deserve to have his pervert of an older brother lusting after him. Or so Papyrus had thought. He could pinpoint the exact moment when he realised that Sans felt the same way about him. It had been a few months ago when he had been searching for his last carton of smokes and had stumbled upon Sans doing their laundry in the wash room. He had been about to open the door and ask Sans if he knew where they were, but what he saw had made him freeze in his tracks.

He hadn’t realised that part of Sans’s cleaning routine involved him having his face pressed into Papyrus’s dirty hoodie.

_With a hand palming his crotch._

Papyrus had stopped himself from getting caught peeping by slapping a hand over his open mouth. It had only been a split second before Sans stopped himself and carried on loading up the machine, but there was no denying what Papyrus had seen. He had not only caught his ‘innocent’ baby brother doing something perverted, but it had been with _his_ clothes. He abandoned his search for his smokes, teleported upstairs, and fucked the living shit out of his hand until tears were running down his skull. Just thinking about how hard he had cum for days afterwards was making Papyrus shiver as he lent against the back door. He had a lot of regret over not just flinging open the door and making a move on his brother, but the likely hood of that ending well was pretty low. Even though nothing had happened between them it had definitely set a course of events in motion that led to tonight. 

There was no point in dwelling on missed opportunities though. Papyrus moved onto his next task of closing curtains, worrying in the back of his mind that their over preparation would make other monsters suspicious. Sans had made anyone and everyone aware that they were planning a movie night, but still that didn’t warrant having their entire house closed off. He had to remind himself that no one would ever suspect anything since they were brothers. _and brothers weren’t meant to do this kinda shit._. He glanced nervously at Sans as he passed him again, noticing that he had been stuck stacking the same place mats for the past five minutes. Papyrus wondered for the hundredth time whether his brother was having second thoughts about tonight. But then no one was forcing him to be here. 

They hadn’t explicitly said their plans for tonight out loud, but they both knew what was going to happen. It was as obvious as the tangible tension in the room. 

Papyrus tried to focus on the task at hand, making sure everything in the house was shut up tight _just in case_. But he couldn’t get thoughts about other ‘incidents’ that had led up to tonight out of his mind. Particularly what had happened on the night that they had almost given in to their feelings. Considering it had been the tipping point where they could no longer deny what was happening between them, Papyrus shouldn’t have been too surprised that he was fixated on it. 

It had been another few weeks of Papyrus barely being able to hide his newly renewed lust after the Seeing Sans touching himself. He had gotten off thinking about his brother more times than he could count, but his hand just didn’t compare to what he really craved. He had tried to be as normal as possible with Sans, convincing himself that the tension between them was all wishful thinking. But then things had come to a head. He could recall what had happened perfectly, even down to being able to hear the sound of the NTT special in his head. 

_The build up to what he was about to do had been so mundane that Papyrus didn’t realise he’d made a mistake until he was watching his brother strip. Sans had been training with Alphys all afternoon, making bones ache so much that he was finding it hard to focus when he couldn’t get comfortable. Papyrus hated to see his brother suffer so he had offered to give him a back rub without a second thought. Sans had seemed reluctant at first, but after some teasing and threats of a tickle fight he had allowed Papyrus to pull him into his lap._

_He knew that Sans’s ‘battle body’ needed to be taken off to be able to do this properly, but for some reason he hadn’t considered that would mean he would end up having a topless Sans in his lap. Papyrus couldn’t remember the last time he’d seen his brother’s naked bones this close, but just the thought of running his hands over Sans’s smaller frame was making it hard to focus. He had to shake his head to snap himself out of his perverted thoughts. Sans still didn’t know that he’d caught him doing things in the past, and there was no way Papyrus was going to make his baby bro feel uncomfortable by bringing it up. For all he knew it was a one time thing; he was certain Sans was a late bloomer sexually, and he probably didn’t understand what he had been doing. He had to put his own perversions aside, be a responsible older brother, and help Sans in his time of need._

_He had started slow, resisting the urge to let his hands go where they wanted to and focusing instead on the spots where Sans seemed to respond the most. But rather than help keep his cool, it had only made everything a million times worse. Sans was vocally appreciative about everything he enjoyed; but there was something so subtle and enticing about hearing his contented murmurs so close. Without thinking properly Papyrus had begun to seek out more of the heavenly sounds, varying the pressure on his brother's back until he started squirming._

_Everything changed when Papyrus accidentally brushed against Sans’s spine, making him gasp loudly. With his vantage point and their height difference he was able to just about able to see his brother’s expression. Sans had his eye sockets screwed shut, his mouth open slightly, and his skull was peppered with a light blue blush. If he was being honest, Papyrus couldn’t recall ever seeing anything as incredible as Sans’s face in that moment. And gods he needed more. He coughed to hide his nerves before he worked up the courage to speak, needing to hear how his baby bro’s voice sounded when he was this far gone._

_“i-is this helping?”_

_“Yes, Very Much So.” Sans gasped again and arched his back as Papyrus trailed the tips of his fingers down Sans’s sensitive spine. “It Feels So Good Papy”_

_Hearing Sans say his name like that, so breathless and dreamy, had sent a jolt of arousal straight to his pelvis making his magic form in an instant. Papyrus didn’t know what to do; he couldn’t stop and risk making Sans uncomfortable, but if he continued there was no telling if he’d be able to stop. He was frozen- rapidly running out of time before it got really awkward. Instinct took over as his mind shut down and Papyrus’s hands moved on their own, heading straight for all the places he’d been too afraid to touch before._

_Starting with a firm stroke of Sans’s spine._

_“Brother I-” Sans gasped as another jerk of his spine pressed him back into Papyrus’s growing erection, his skull flushing further but still he made no move to run away. “Oh Stars!”_

_There was no mistaking the moan that fell out of his baby brother’s mouth, nor Papyrus’s own hiss of pleasure as he continued to slide his fingers in between Sans’s sensitive bones. He’d never had anyone else touch his spine like this, but from his own experimentation he knew just how incredible it could feel. He was making Sans feel good; he’d been hurting, and Papyrus was just being a good brother and making it better. Papyrus would have been able to convince himself the situation was sweet if his cock wasn’t currently growing harder by the second._

_They were both panting heavily when Sans shifted in Papyrus’s lap to face him, inadvertently grinding his tail bone against his cock. Papyrus had to bite his tongue to keep from actually moaning, but all of the air felt like it was being sucked out of him when he and Sans made eye contact. In that moment so much understanding passed between them. It was obvious they were both teetering on the edge of giving in, that the attraction between them was so strong it becoming impossible to resist. He could fucking **hear** both of their souls beating as one. _

_Papyrus had been moving one of his hands to cup his little brother’s face when a knock at the door had brought reality crashing down around them._

The rest of that evening had been a blur of awkwardness as Sans tried to busy himself with preparing dinner for Papyrus and a very confused Alphys. She had only popped over to drop off some extra training gear for Sans in the form of a chef’s hat and apron, but Sans had been quick to invite her in. Papyrus had been stuck concealing a boner behind a nearby cushion and making small talk while Sans over compensated with some enthusiastic cooking. The situation may have been uncomfortable, but Papyrus thanked the stars that the captain hadn’t shown up a few minutes later instead. Their door had been unlocked, and he didn’t really want to have them being discovered, ruining something that hadn’t even had a chance to start. 

Just the memory alone was almost too much to handle, Papyrus could feel excited magic buzzing around his bones. Coupled with his nervous energy it was a miracle he had been able to walk at all, let alone manage to start making his way back towards the couch. With every precaution taken to shield them from prying eyes there was nothing else standing in their way. He picked up the remote and started to flick through the channels absent-mindedly, listening out for any signs that Sans was ready to join him. 

He was anxious, but no amount of nerves would make him think this was a bad idea. He remembered the few days after the incident on the couch where he and Sans tried to avoid each other completely. Sans had spent all of his free time doing extra training and Papyrus had gone so far as to try and convince Muffet to let him sleep in her cafe. But no amount of time apart changed how he felt, and one look at his brother’s face told him that Sans felt the same way. In fact the only thing trying to stay apart did was make them both feel like utter shit. 

They knew they weren’t meant to feel this way about each other… but knowing that didn’t make the feelings go away. 

Staying away from each other wasn’t an option. Papyrus would have been fine with continuing to try and hide his feelings, but that night had been a taste of what they could have. And he was fucking _starving_ for more. They had tried to move forward together in an unspoken truce of trying to ignore what happened, but all that was doing was making them yearn for more. Papyrus had tried to get back to that comfortable closeness they had always had, but the slightest bit of contact would send them both running to their respective rooms. He wasn’t sure what was worse; the fact that he had his dick in one hand and the handle to the door in the other, or that he could _hear_ Sans doing the same thing. 

This went on for weeks. Sometimes Papyrus got so close to breaking that his whole body would scream at him to go into Sans’s room and give them both what they needed. It seemed so stupid for them both to keep denying themselves what they were craving when it was obvious what they both wanted. Even though he hated to admit it, deep down Papyrus knew what was holding them back. It was no longer a case of what they should and shouldn’t do, but more how could they explore these feelings without getting caught. 

They needed time alone, completely undisturbed, and as soon as possible.

Which was probably why Sans had spent the entire week hinting at wanting to have a ‘movie night’ together. Originally Papyrus had thought nothing of it and had been half way through agreeing when he had noticed his brother’s face. Sans was flushed, his breathing uneven, and he was unable to make eye contact at all as he waited for an answer. Putting two and two together Papyrus had figured out the subtext, tripping over his words to blurt out an enthusiastic yes. The atmosphere was tense, but they had both laughed nervously with the biggest grins on their faces. The rest of the week had been spent in silent preparation for tonight. Although both he and Sans had become more than a little jumpy, Papyrus knew that the pay off was going to be worth any amount of awkwardness that they had to go through first. 

Sans coming to join him on the couch snapped him back to the present. Papyrus had been so lost in his thoughts that he had only noticed Sans when he was picking up his legs so that he could sit on the other side. Considering laying sprawled out on the couch was what Papyrus always did, this way of sitting came naturally to them both. But with everything else that had been going on between them the simple action felt far more intimate than usual. Papyrus fought the urge to swing his legs out of his brother’s lap at the same time as fighting the desire to throw his whole body on top of him. Instead they both sat there, not talking, while Papyrus kept circling around the undergrounds limited amount of channels. 

It dawned on Papyrus that neither of them had actually picked a movie to watch for tonight, their focus being on everything but choosing a film. It was a testament to just how worked up they both were, and it made him shiver with anticipation. Papyrus managed to find something half decent that he knew Sans would enjoy to he just let that play. He didn’t plan on paying attention at all, so it didn’t matter what it was. He feigned interest for all of five minutes before letting his eyes wander over to his little brother. In his opinion Sans always looked great, but there was just something about his ‘battle body’ that would drive him crazy with fantasies. 

This close Papyrus was able to admire the small parts of exposed bone between the end of his t-shirt and the start of his gloves. The question over how much Sans was going to keep on as the night progressed flashed through his mind and made him almost have to clamp a hand between his legs to stop his cock from forming too soon. Papyrus had fantasised about being with Sans in various states of undress, but he wouldn’t mind if his baby bro was too shy to strip down completely. In fact there was something so delicious about doing things with Sans when he was wearing this outfit, it would just remind Papyrus that it really was his sweet little bro in bed with him. He knew that thinking that shit, as in actually getting off on the fact that Sans was his brother, was pretty fucking sick. But that’s what made the desire so hard for Papyrus to ignore; the more taboo it felt, the more he wanted it. 

Sans seemed to be doing a better job at pretending he was paying attention to movie. Papyrus had picked a comedy mainly because he couldn’t get enough of his little brother’s adorable laugh, and it was definitely dispelling some of the nervous energy in the air. Though that didn’t last. One particular gag had Sans throwing his hands up in the air in mock announce only to bring them back down to rest on Papyrus’s legs. Cheesy as it sounded, Papyrus could have sworn that the simple gesture sent a jolt of magic across his sensitive bones. He clamped a hand over his mouth immediately to stop any sounds escaping. But it was too late. Sans’s soft blue eye lights were fixed on his face. 

But he didn’t move either of his hands away. 

Papyrus could feel his skull burning as brightly as the blush lighting his brother’s face up. Sans had focused back onto the t.v but started to move his hands up Papyrus’s legs with soothing strokes. Papyrus was giddy with excitement over the implications of what his brother was doing. There wasn’t any external reasons to stop what they were doing now, they had effectively walled themselves off from the underground for the night to be able to do whatever they wanted. He could feel that build up of tension flooding back as Sans’s hands didn’t stop their movements, the metaphorical wall between them crumbling more by the second. Papyrus had been panting heavily into his hand, but couldn’t fully stifle the groan that escaped him when one of Sans’s hands caressed the inside of his femur. 

Sans jumped at the sound and pulled his hands away. _shit!_. Papyrus had let himself get swept up in the moment without a second thought as to how much of a big step that little gesture really was for them both. Sans didn’t say anything else but Papyrus could see how much more flushed he was as he went back to watching the show. Papyrus couldn’t shake the feeling that his chances for this evening were slowly slipping away. He should have known that his lust for his little brother was clouding his ability to think, he was even starting to wonder whether this really was just a poorly planned movie night. He couldn’t believe he’d been so stupid.

Just when he thought the situation couldn’t get any worse, it seemed like he’d managed to make Sans so uncomfortable that he was pretending to yawn. Papyrus let Sans untangle himself from where they were sat on the couch, no longer seeing the point of trying to get him to stay any longer. Papyrus had almost given up hope as Sans was leaving, resigned to yet another night alone with his hand and self-hatred, when he realised that Sans had paused behind the couch. 

“Well P-Papyrus I’m Going Upstairs, To My- To My Bedroom.” Sans stuttered, but there was a distinct sound of something else in his voice. 

Something that Papyrus had only heard on that night where they had almost…

“So That’s Where I’m Going To Be, All Night Long” Sans was inching towards going upstairs, but not before adding more in a voice just above a whisper. “Papy, I Hope You’ll Um- I-I Hope You’ll Come T-To See Me.”

Papyrus was completely stunned considering he had all but given up hope moments ago. “sure thing bro. i-i’ll be up in a sec” he replied without being able to look at Sans for fear of jumping him right there if his brother’s face was as full of desire as his voice was. 

If Sans needed to do this on his own terms, where he felt the most comfortable, then Papyrus was going to do everything he could to suppress his urges just a little bit longer. 

He heard Sans practically running upstairs and opening his bedroom door, but not closing it behind him. _fucking hell sans_ Papyrus was losing his mind over his younger being the one to make the first move, giving him an open invitation if he could just get the pounding of his soul to calm down. But then… he didn’t want to lose this rush. The mix of nerves, excitement, and desire was a rush unlike anything he’d ever experienced. There was no point in going through all of this alone either, not when the object of his affection was waiting for him upstairs.

Papyrus stood to his feet before he lost his nerve, not wanting to keep his little brother waiting any longer. There was no way in hell he was going to let Sans sit upstairs alone, wondering if he was going to show up. _who gave a fuck if he seemed eager?_ Papyrus didn’t want to play any games with so much at stake, he wanted Sans to know without a doubt how much he wanted this. He hesitated at the door, his nerves popping up again when he realised that everything between them was about to change. But shook his head and opened the door with a smile. Knowing Sans was at least ready to try and see what could happen between them was the only thing that mattered right now.

Sans hadn’t turned his bedroom light on, the blue magic lighting up his face being the only light source in the dark. It was almost poetic how Papyrus felt instantly drawn to him, quickly sitting himself down opposite his little brother on the bed. There was no denying that Sans looked nervous, but there was so much more sparkling in his eyes. Without meaning to Papyrus was already leaning down towards him, his soul beating harder than it ever had in his entire life. He just couldn’t believe that he was lucky enough to have such an incredible skeleton in his life, let alone get over the fact that Sans felt the same way about him. But he knew how much of a big step this was, for both of them, and he didn’t want Sans to feel like they had to do anything that he was uncomfortable with. 

Papyrus brushed his thumb over his brother’s face, something that he had done a million times before but now felt like it meant so much more. “you’re so beautiful sansy” he gasped, unable to fully control all of the feelings that were bubbling to the surface. “But we don’t have to do this if you-”

“No!” Sans cut him off with a shake of his head before his eye-lights all but disappeared. “S-sorry I Didn't Mean To Yell. But I Really Want Y-You So Much. I Can’t Think Straight Any More”

Papyrus knew exactly what he meant, just being close to his little bro knowing what was going to happen was making it hard to even breathe. He leant forward until their foreheads were touching, feeling Sans shiver when he placed one of his hands over his brother’s smaller one. He wanted to commit everything about this moment to memory; the sound of their soft panting, the faint scent of leather and sweat, and the feeling of _finally_ being able to hold him this close. 

“tell me if you want me to stop at any point, ok?” Papyrus whispered, waiting for his brother to nod before leaning in for a kiss. 

Papyrus wasn’t sure who was moaning when their teeth pressed together, but he was sure he was the one to deepen the kiss almost instantly. He pressed his tongue into Sans’s open mouth, shivering when he found his brother’s own already formed and eager to connect with his. His head was swimming in bliss. This was really happening. He really was on his little brother’s bed and kissing him like his life depended on it. _and sans was kissing him back_. The deep kiss was absorbing most of their noises, but this close Papyrus could feel how Sans’s whole body was vibrating with repressed moans.

Without thinking he let one of his hands drift towards his brother’s arm, wanting both to give Sans something to steady him and needing to feel more of him. Sans froze a little at the touch, and Papyrus withdrew his hand thinking that his brother just wasn’t ready for more yet. He didn’t expect Sans to grab his hand and bring it back, shifting himself forward on the bed so they could be closer. The kiss became more intense as the experimented with holding onto more and more of each other until Sans had practically crawled into Papyrus’s lap, his whimpers and moans steadily increasing in frequency. 

Withdrawing from the kiss was almost painful, but with the amount of other things going on it was becoming hard to even call what they were doing a kiss any more. Sans looked a little confused, but that wasn’t what Papyrus was focusing on as his eyes flicked all around his brother’s trembling form. Sans’s eye lights were blurred and his expression dreamy as his tongue lolled out of his mouth. There was a thin trail of magic still connecting them both, lit up from the joint glow of their magic through their clothes. The fact that Sans’s magic was already excited was made Papyrus whine with need. They had only just started but already this was so much better than anything he could have ever imagined. 

It was obvious that they both needed more, but Papyrus couldn’t make up his mind on what he could do that wouldn’t feel like too much too soon. His mind was all over the place but he managed to cling to a passing thought about how much better it would be to caress his brother’s sensitive bones now that he could do it properly. He moved the hand he had on Sans’s arm slowly up under his shirt, smirking when his little brother’s body arched into his touch. It felt amazing to be able to touch exactly where he wanted to; skimming his hand down Sans’s rib cage before teasing one of his floating ribs between his fingers. Sans arched further into him, his sockets screwing shut as he lost himself to the incredible feeling. 

“do you like that?” Papyrus asked while rubbing the bone in his grasp a little harder. He knew the answer, but he still couldn’t resist asking if it meant he could get Sans talking.

“Mweh, Brother-” Sans blurted out before flushing even brighter, visibly ashamed at losing himself like that. “Oh I-I Mean- P-Papyrus!”

Papyrus had to chuckle a little, Sans was just so cute. He knew he could react in one of two ways at being reminded that they were brothers, it was obvious that Sans was a embarrassed about it, but his cock made up his mind for him.“you don't have to stop that you know.”

“Stop What?”

“calling me bro, its really. heh. turning me on” Papyrus confessed, pressing his cock against Sans’s pelvis so his brother could feel how hard he was. 

“Oh. _Oh._ ” Sans’s sockets became lidded as he rocked against Papyrus slowly. “Please Continue- Big Brother- Th-This Feels Really Good.”

Their teeth clashed painfully when Papyrus moved in for another kiss but neither of them cared. Hearing Sans say _that_ had almost made Papyrus cream his pants, and now he couldn’t control the way he was grasping at his brother needily. His hands slipped lower, grabbing hold of Sans’s spine and stroking it firmly. Sans whined and moaned into his mouth as Papyrus stimulated him until he was trembling. Papyrus was momentarily confused when the room suddenly became lighter, but it felt like his wildest dreams had come true when he realised the glow was coming from his brother’s shorts. 

“saaanns.” Papyrus voice was ragged and breathless as he gave Sans hard kisses at every chance he got. “oh shit- you're such a good boy-” his own cock was straining against his slacks as he moved a hand to rest on the bulge in Sans’s short. “-can i?”

“Stars, Papy! Please!” 

Papyrus tore the flimsy material of his brother’s shorts when pulling them off, but seeing Sans’s cock spring free made it hard to have any regrets. Sans pulled his shirt up to bunch around the top of his ribcage, giving Papyrus an even better view than before. He wrapped one hand around his brother’s spine again and the other around his cock. Papyrus hissed through his teeth when he felt the soft magic against his fingers, with the dribble from the head of his Sans’s cock giving him more than enough to be able to stroke him with ease. He moved both of his hands in tandem, bucking his hips against Sans’s leg as his brother’s sweet sounds made his own need impossible to ignore. 

Sans was falling apart right in front of him; his face screwed up in pure pleasure as Papyrus slowly increased the speed of his hands. He seemed so far gone, so Papyrus was completely surprised when Sans flipped their positions and pinned him down on the bed. 

“Papy! I Can't-” Sans started grinding his cock against Papyrus’s still clothed one, making them both almost choke with how amazing it felt. “Please Let Me- I-I Need You So Much” 

“s-sure thing bro” 

It didn’t matter what Sans wanted, he was going to go along with it. He was set on giving his little bro everything he desired. Sans’s hands worked fast in completely removing his pants as well as pushing up his hoodie to expose his ribcage. Papyrus guessed that Sans wanted to try what he had been doing to him, so he relaxed back on the bed and prepared to lose his mind over his brother touching his dick. But Sans’s hand dipped lower, softly probing at the entrance near the back of his magic. Papyrus gasped in shock, stunned into silence when he felt Sans press a little harder. 

“sans? what are you-”

“You Need Stretching Out Right?” Sans offered the answer with a wink. He pulled away for a second to remove his gloves but paused, a devious look taking over his cute features. “Actually I’m Going To Keep These On, I’ve Seen The Way You Look At Them Papy”

Any protests that Papyrus had died on his tongue as he watched Sans bring his fingers to his mouth and wrap his thick blue tongue around them. Sans’s other hand was rubbing across his chest, the sweet drag of leather on bone making him whimper like a bitch in heat. While this wasn’t exactly what he expected, he’d had so many fantasises over the years about his sweet little brother completely taking control of him. He was nervous...but Sans’s expression was making his head spin so much that he didn’t even notice his fingers were pressing inside until he felt them slip into his ass. 

Papyrus arched in a silent scream; the invasion coupled with how much heat there was between them making it feel so much more intense. Sans was quick to compensate any discomfort he may have been feeling by lowering his face towards Papyrus’s rib cage. He still had one hand entwined between his ribs but the feeling Sans’s tongue lapping some of his most sensitive spots was incredible. Papyrus almost lost it when Sans made eye contact with him while wrapping his tongue around one of his lower ribs. Sans looked so fucking sinful and yet his eyes still sparkled with that childlike wonder that he never seemed to lose. It felt like he was falling for Sans all over again. Even while his fingers were buried deep inside him. 

Another low moan was drawn out of Papyrus when he felt Sans start to scissor his fingers. “holy shit bro-ah! have you done this before?” he asked with a breathless laugh, still unable to believe how amazing it felt. 

“A Few Times-” Sans replied in between more kisses and licks to Papyrus’s ribs. “Only To Myself-” he added when he noticed Papyrus’s slight pout. “I Like To Imagine You Doing It To Me Instead”

Thoughts of Sans finger fucking himself while thinking of him made Papyrus almost blow his load. “stars sans, i-i-i- hhhn!” he was babbling with need, his previous fears being over-take by an overwhelming desire for more. “i need you inside me. i need you baby bro, please!” 

Sans was past smirking or teasing now, and Papyrus filled away his brother’s reaction to begging away for future use. But now the only thing on his mind was the feeling of his little brother’s thick cock pressing at his entrance. Sans had hooked one of his legs over his shoulder to give him a better angle and it only took a few experimental thrusts for him to slip inside. Sans had to pause and pant heavily when he managed to sink all the way in. Papyrus couldn’t tell if he was just overwhelmed or if he was just as close to cumming as he was. There was a brief flash of regret where Papyrus cursed himself for all the wasted time they spent skirting around each other, but it was all forgotten when Sans started to move inside him. 

Their pace lacked finesse, but that didn’t matter when Sans was pounding into him with so much passion he was worried he might break. Papyrus tried to keep some of his composure but to no avail. Sans’s cock felt thick and hot inside him, and the way it was sliding inside his inner walls was making him see stars. He was soon practically a screaming mess, sweat dripping down over his skull as he rocked his body to meet Sans’s thrusts. Their height difference and position they were in made it hard to kiss but neither of them could keep their hands off each other. Sans was finding spots on his body that Papyrus had no idea could feel this good. But when his little bro wrapped a hand around his spine so he could use it to pull Papyrus onto his cock harder, Papyrus felt the last shred of his control snap. 

“bro, i control myself- i’m ah!” Papyrus arched his spine into his brother’s hand and screamed again as Sans bottomed out inside him. He was so close he could taste it. “it feels so good. please, i can’t cope!”

“I Don’t Care Who Hears You” Sans bucked into Papyrus harder, his tongue hanging out of his mouth as he lost himself completely. “I-I Want To Hear You Scream. You’re Mine. Mine! I’m Going To- Ah! Papy! I Love You So Much!” 

Papyrus tried to return the sentiment but Sans’s gloved hand wrapping round his cock made it come out as a garbled mess. He could feel his climax approaching fast. Papyrus grabbed onto any part of Sans he could reach as he moaned his brother’s name and came on his cock. Sans thrust twice more before shaking all over and filling Papyrus up with hot magic. He pulled out a little quicker than felt comfortable, but Papyrus’s whines were silenced when he realised it was so they could kiss again. He pulled his little brother as close as possible, enjoying the press of their bones together as they came down from the high. 

The aftershocks eventually died down but the kisses didn’t. Now they had gone all the way it felt like it was impossible to keep their hands off each other. They made out while holding each other close, slowly drifting to sleep in each others arms. Papyrus knew that Sans was going to be annoyed at the mess in the morning, but they were both so exhausted by how on edge they had been all week that sleep came quickly. They could deal with being back in the real world tomorrow, tonight the only thing that mattered was being with each other. 

*********************************************************************************************************************************************************************

Waking up in Sans’s bed had been confusing, but the morning make-out session certainly helped Papyrus get his bearings. Surprisingly there wasn’t too much awkwardness between them in the light of day, everything just felt so right with his baby bro in his arms. But like all good things, it had to come to an end eventually. Sans wasn’t impressed when he realised what time it was, and even less so when Papyrus refused to stop running his tongue across his vertebrae.

“Papppyy” Sans continued to squirm as he tried to untangle himself from his brother’s vice grip, but all that did was made it harder for him to escape. He started giggling over how ridiculous it all was, his laugh being so infectious that Papyrus couldn’t help joining in. Eventually they calmed down enough for Sans to plead his case a little more. “ C’mon Papy. Heh. I _Really_ Want To Stay, But I’m Going To Be Late For Morning Patrol”

“fine.” Papyrus huffed and let his brother go before snuggling himself back into bed. He didn’t miss the way his little bro looked at the mess they had made last night with a face full of concern. “- before you ask. no- i won’t spend all day in bed, and yes- i’ll make sure to put everything in the wash.”

“You’re The Best Papy!” Sans leaned back in to kiss him on the forehead like he always did, adding an extra kiss on his teeth before trying to locate something to wear. 

Papyrus zoned out most of the noises his brother made while getting ready, that coupled with the sounds of the rest of Snowdin waking up were soothing in a way. When Sans had left with a cheery goodbye Papyrus had sank back into the mattress with a sigh, deciding to try to have a small nap before having to face the real world. But he couldn’t fall asleep. Papyrus kept seeing snippets from last night every time he closed his sockets and soon the sounds of the town outside wasn't the only thing keeping him awake. Being alone with a boner caused by his little brother wasn’t a new feeling, but he felt even more frustrated than usual. Now that he and Sans were together it seemed like a waste to touch himself when they still had so much more to explore with each other. 

That got him thinking. Last night had been amazing but there was still so much he wanted to experience. He wanted to explore every inch of his brother, to take that pretty blue cock in his mouth, and to know what Sans looked like while Papyrus fucked his face. But most of all he wanted to know what it felt like to have his cock inside his little brother’s body. A lecherous smirk formed on his face as he remembered something Sans had said the night before. As soon as he had pulled his pants back on he was trying to remember his brother’s routine, choosing a spot nearby to teleport to so he could surprise him. 

Sans was just where he had expected, barely out of the town and just making his way towards the overlook. While this early in the morning there wouldn’t be too many monsters around this area, it still posed a significant risk of someone crossing their path. Which couldn’t have been more perfect. Papyrus felt like a predator stalking his prey as he came up behind his brother, circling his arms around him from behind. 

“Mweh!” Sans gasped in shock as he struggled against his captor. “Who Dares Apprehend The Magnificent Sans?!” 

_this was too good._ Papyrus leaned into the squirming skeleton in his arms, making sure to tickle Sans with his hot breath before speaking. “take a guess.”

“Papy!” Sans sounded giddy with excitement before he realised that Papyrus was slowly moving him to a nearby inlet in the cliffs. “What Are You Doing?”

“i got lonely-” Papyrus murmured against his brother’s skull before turning him around and moving one of Sans’s hands rest on his prominent erection. “-and i couldn’t stop thinking about you”

Sans’s reaction was priceless. His entire skull turning blue in an instant as he struggled to find the words to express how embarrassed he was. “P-Papyrus!” he finally managed to get out while pulling his hand away as if Papyrus’s cock was made of fire magic. “We Can’t B-Be _Lewd_ Here!” 

“why not?” Papyrus followed Sans as he backed away until he had boxed him in against the cliff side. He moved one arm against the wall of rock to block Sans from escaping while trailing fingers down the front of his brother’s shirt. “didn’t you say last night about how you didn’t care who heard us?”

Sans was cornered and his bones were shaking. Papyrus almost thought he had gone too far and was about to pull his brother into a comforting hug when that tell tale glow from his brother’s shorts started to shine. He knew he had been right about Sans enjoying the risk of being caught, he guessed that the thrill and the lasting implications were just too good for to resist. Papyrus had only been able to pick up on it, because he was exactly the same. But Sans was still blabbering, still fighting with himself on giving in to what they both wanted. It seemed like Papyrus needed to take the lead and persuade him. 

“i-i- that’s d-different! i-it’s not what i-”

“feeling a bit tongue-tied sansy?” Papyrus used the hand he had on the wall to push his brother to his knees, making him blush even further when he pulled his throbbing cock out of his pants. “how about you let big bro give you something else to do with your mouth?”

Papyrus watched as a dozen emotions flicked across his brother’s face, the tension in the air unbearably thick until he saw a blue tongue flick across the head of his cock. Sans gave a few sheepish looks around where they were barley hidden before taking Papyrus into his mouth fully with a moan. His pace was shaky, a sign of his lack of experience, but Papyrus was biting on his hand regardless to keep from being too loud. There was just something about seeing his honey coloured magic with a blue tongue wrapped around it that he couldn’t get enough off. 

But Sans was moving a little too slow. Usually he’d be all for a long session of oral, but that could come when they had more time at home. He grabbed the side of Sans’s skull and started to move him on his cock faster until he was fucking his face roughly. Papyrus lost himself to the feeling momentarily, only realising he was going too hard a little too late. One look at Sans reassured him that his baby bro was fine with his eyes lights taking on the shape of little hearts.

“fuuuuck sans-” Papyrus groaned as his grip on his brother’s skull tightened. He could see the way Sans was squirming in the shorts that by now looked far too tight. He wondered just how much further he could push him. “-how about you show me how you fuck yourself with your fingers?” 

Sans moaned around his cock, his hands moving to pull his shorts down without hesitation. Papyrus eased his grip on Sans’s skull, allowing his brother to gather some of the liquid magic on his cock to lube up his fingers. He had expected Sans to need a little more persuading, but it was like a switch had been flipped as soon as he had pulled out his cock. He took in the scene before him; Sans on his knees- in the snow- with hearts in his eyes-and his fingers in his ass. He’d never seen anything more alluring, or felt more in love.

Papyrus let Sans continue for a few minutes until his brother’s moans started increasing in volume. He pulled Sans off the ground, pulling his shorts off one leg completely, and pinning him against the wall. Sans caught on quickly, wrapping his leg around his brother’s back and making the head of his cock push against his entrance. Papyrus saw no point in wasting any time, but he penetrated his brother slowly so that he could soak up every tiny shift in his expression. Sans looked absolutely sinful as Papyrus’s cock slipped inside, their joint magic showing in his pelvic inlet. Papyrus had to place a hand over his brother’s mouth to muffle his moans. 

For someone who had been protesting about fucking in public, Sans was being awfully loud. 

“you really like this huh?” Papyrus said in a hushed tone, moving the hand that wasn’t supporting his brother’s weight up under his shirt, picking up where he left off last night by dragging his fingers down his spine. “you’re really loving having your big bro fuck you where anyone could find us, right sansy?”

“Paaapppy, You’re So-Ah! I Need- I-I- Need-”

“what?” Papyrus drew almost all the way out of his brother’s heat before pulling Sans back down onto his cock. “what do you need?” Sans was whimpering and looking around, struggling to say anything ‘lewd’ even with Papyrus hilted inside him. “you’re so fucking cute. you had no problem saying it last night though- do i need to do this a little more?”

Papyrus pushed his fingers in between his brother’s vertebrae, swallowing his moans with a kiss. He could feel Sans’s inner walls starting to flutter around his cock as tears streamed down his face. But he was kissing Papyrus harder than before, moving as much as he could to meet his brother’s thrusts. Papyrus looked between them again, watching as his cock distorted his brother’s magic with every thrust. He could also see Sans’s cock sandwiched between them, leaking magic as it throbbed heavily. Knowing that his little bro was close already was driving Papyrus towards the edge, but he wanted to see Sans fall apart first. 

“you could probably cum with me just doing this, couldn’t you?” Papyrus’s voice was strained, barely able to keep his own noises in check any more. “-i bet you’re gonna cum all over me just from me stroking your spine with my cock deep inside you? fuck baby bro, that’s really hot”

“Please! I Can’t- Hmf!” 

Papyrus had to clamp his hand over Sans’s mouth prematurely as he heard something else in the distance. It sounded too much like the shuffle of snow and footsteps for comfort, but both of them were too close to be able to stop now. In a moment of clarity he held Sans close, teleporting them both back into the comfort of his bedroom. Without the support of the cliff Sans’s shoulders fell back onto the bed while Papyrus continued to pound into him from a kneeling position. He had one hand gripping his brother’s hip while moving the other towards his cock. 

Sans’s body started to shake as his cock pulsed in Papyrus’s hand. He arched himself up of the bed and cried out without any form of restraint. “Papy! Brother Please! Oh Stars, I-I’m Cumming!” 

Papyrus wasn’t sure what actually tipped him over the edge; Sans’s walls tightening around him, being able to see so much of his brother’s incredible body, or watching Sans cum all over his own rib cage. He bottomed out inside his brother with a shout of his own, continuing to roll his hips and ride them both through their intense orgasms. He pulled out of Sans carefully before laying him down on the bed, wincing and hoping his little bro was too relaxed to notice he hadn’t got round to changing the bedsheets. But then again, it had turned out for the best. Sans loved cleaning but even he would complain about having to wash his bedding twice. Papyrus hummed happily as he joined him on the bed and brought his brother into a hug. It was Sans’s little nuances, his habits that seemed over the top to others, that he adored. He knew that was lame, but then it was hard not to be all loved-up after doing what they had done. 

“Papy, That Was-” Sans said breathlessly, throwing his hands up in the air to demonstrate his loss for words. His expression turned serious for a moment as he turned to his brother and playfully pushed him on the shoulder “-But We Almost Got Caught!”

“heh, don’t worry bro-” He soothed a thumb over his brother’s cheek, watching as those dazzling eye-lights lifted to meet his gaze. “it’s fun to play these games, but i wouldn’t want to actually put us in danger. which is why I brought us back here so quickly, but i understand if you’d rather not do something like that again. 

Sans started to turn blue again and he laughed nervously while scratching the back of his skull. Sans wasn’t able to look his brother in the eyes any more, something which had Papyrus’s focus instantly pulled. 

“Actually I Really Enjoyed It. A-And I Had An Idea For A Spot In Waterfall, It’s Right Next To-”

Papyrus’s lust clouded mind filtered out the rest of the details. He was too fixated on his little brother’s cute face, the way he struggled over some of the words, and the way his bones were starting to glow with magic again. Papyrus was immediately on board, hell he was pretty sure he was going to be ready to go again if that’s what Sans wanted. Before last night Papyrus would have been willing to do anything to make his baby bro happy. He considered himself to be the luckiest skeleton alive because now what made Sans happy was being with him.


End file.
